According to this KernelTrap article, the 0.11 Linux kernel was released on December 8th, 1991. Among the 'features' advertised in that release, Linus noted that the console was now capable of producing beeps, Linux gained native mkfs, fsck and fdisk utilities, and the com ports finally had adjustable line speeds. However, if you managed to get Linux booted you were immediately dropped into a root bash shell as Linux lacked a login system. It also lacked support for SCSI devices, and support for swapping to disk meaning it required at least 4MB of RAM to be useful.